The present invention relates to an organopolysiloxane composition capable of curing into a highly flexible rubbery elastomer upon exposure to ultraviolet light and having a moisture curing function in a shaded place where ultraviolet light does not reach.
Heretofore, curable silicone compositions have been used in various industrial fields because of their various superior characteristics. However, many of them are a heat-curing type, a type of curing at room temperature upon standing for a long time, or a two-pack type, and problems have been encountered in their curing time and working efficiency. For solving these problems, various studies have heretofore been made about a silicone polymer with a certain photosensitive group introduced therein for curing upon radiation of light such as ultraviolet light thereto or about a composition containing such polymer. However, the photocurable silicone polymers or compositions which are presently known involve problems; for example, a photocuring reaction does not always proceed at a sufficiently high speed, or their curing mechanism is apt to be impaired by the oxygen in air. Further, in a shaded place where light such as ultraviolet light cannot reach, there remains an uncured portion.
Accordingly, it is the object of the present invention to provide a novel photocurable organopolysiloxane composition free of the above-mentioned problems encountered in the prior art.